Abstract: An apparatus for dispensing a liquid, the apparatus comprising a chamber for containing the liquid and a gas therein; an outlet in fluid connection with the chamber for releasing the liquid from the apparatus; a pressure-sensitive barrier in the fluid connection between the outlet and the chamber for preventing release of the liquid from the chamber and for allowing passage of the liquid therethrough only when there is at least a critical pressure difference between pressure of the gas in the chamber and atmospheric pressure; and a compressing element for compressing the gas to a raised pressure upon a one-time activation of the compressing element, wherein difference between the raised pressure and atmospheric pressure is at least the same as the critical pressure difference.